With the vigorous development of Internet service and the extensive application of radio network, radio systems such as General Packet Radio Service (GPRS), 3rd Generation (3G), Worldwide Interoperability Microwave Access (WiMAX) and Beyond 3G (B3G) are applied and concerned widely. New requirements for radio access network system to support various services with large-capacity, large data throughout and different Quality of Service (QoS) are arising with the increase of the quantity and requirements of the users.
A radio access network mainly provides forwarding function or routing function for packet service between a service providing network and a mobile user. A main technology of radio access network system is to provide a user with a QoS-based steady data transmission service. The statistic of accounting information (i.e. data amount and service time) which is provided to a user according to the location area, is very important in the communication system. A WiMAX accounting network system as shown in FIG. 1 is an example for the description as follows. Internal devices not related to accounting in the WiMAX access network are not shown in the system.
In the WiMAX access network, an Access Service Network (ASN) provides a WiMAX terminal with radio access services. The ASN comprises a Base Station (BS) and an Access Service Network Gateway (ASN-GW), wherein, the functions of the BS include: (1) radio access function for Mobile Subscriber Station (MSS); (2) radio resource management; (3) measurement and power control; and (4) compression and encryption of air interface data. The functions of ASN-GW include providing the functions for MSS Authentication, Authorization and Accounting. The accounting function entity corresponding to the MSS is identified in FIG. 1. The logic unit of the accounting function entity is located in a certain ASN-GW and other MSS may be located in other ASN-GW. The functions of ASN-GW further include (1) supporting the network discovery and selection of NSP; (2) allocating an IP address to the MSS dynamically; and (3) radio resource management. The ASN-GW may further provide functions as follows: (1) handovering between BSs of the ASN; (2) MSS paging and location management; (3) tunnel management between the ASN and a Connectivity Service Network (CSN), which is equivalent to a Foreign Agent (FA) of mobile IP technology; (4) Authentication Proxy between the ASN and the CSN; and (5) visitor location registration.
In a WiMAX, the CSN provides a WiMAX terminal with IP connection services. The functions of CSN mainly include: (1) IP address allocation of MSS; (2) Internet accessing; (3) function as an Authentication, Authorization, Accounting proxy (AAA proxy) or an AAA server; (4) user-based Authentication control; (5) tunnel from the ASN to the CSN, which is equivalent to a Home Agent (HA) of mobile IP technology; (6) accounting for a WiMAX user and settlement between service providers (the AAA server or AAA proxy as shown in FIG. 1 mainly provides this function); (7) tunnel between CSNs in the roaming case; (8) handovering between ASNs; and (9) various WiMAX services (e.g., location-based services, multimedia multicast services, broadcast services and IP multimedia subsystem services).
The MSS is a mobile user device by which a user accesses a WiMAX network.
In the related art, the MSS accesses a BS through an R1 interface. The AAA client of the BS initiates an authentication procedure to the AAA server via the AAA proxy of the ASN-GW. The AAA server authenticates and authorizes the MSS. The MSS can initiate a QoS-based session for data transmission. The data of the MSS is eventually transmitted to the Internet by an HA through the R1 interface between the MSS and the BS, an R6 interface between the BS and the ASN-GW and an R3 interface between the ASN-GW and the HA in turn. At the beginning of the session, the AAA client notifies an accounting processing unit of the AAA server the information of starting the session, and begins to account. When the MSS or the network side initiates a termination of the session, the AAA client notifies the accounting processing unit the information of ending the session, and reports the accounting information of the MSS. The accounting information mainly includes duration of the session, data volume, authentication and authorization information of the session, and the QoS during the session establishment period.
In the related art, the AAA client reports the information of starting the session when the MSS establishes the session; the accounting information including the QoS of the session is reported. If the QoS of the session is changed during the session, the AAA client does not report the changed information of the QoS, neither report the session duration and data volume of the session with new QoS nor report the session duration and data volume of the session with old QoS to the AAA server respectively. The AAA server only accounts according to an accounting strategy corresponding to old QoS on the session establishment.
The MSS requires to change the QoS during the session under the WiMAX protocol. However, in the related art, the accounting can only be performed according to the accounting strategy corresponding to the QoS on the session establishment. If the MSS adopts a QoS with a high tariff on the session establishment and changes to adopt a QoS with a low tariff during the session, but the AAA server accounts for the session according to the QoS with high tariff; this accounting method is unfair to the users. If the MSS adopts a QoS with low tariff on the session establishment and changes to adopt a QoS with high tariff during the session, but the AAA server accounts for the session according to the QoS with low tariff; this accounting method is unfair to the service providers.